MixSID Dual SID Board

While me and couple of hundred other SID fanatics are waiting for the SIDFX units to arrive, a new advanced dual SID board design appeared out of the blue; MixSID by Henning Bekel.

The arrival of MixSID is quite interesting, as feature-wise MixSID appears to be on-par with the SIDFX. Want to install any two SID models to any C64 model? Be able to switch between the installed SIDs on the fly? Choose between mono, dual-mono or true stereo operating modes? Have flexible selection for the second SID address space? Adjustable digi-boost for 8580? Volume level balancing for the installed chips? Reduced noise?

Check.

Both SIDFX and MixSID are capable with the above, and more. Of course SIDFX has even more some interesting features, including software configuration for the settings, and automatic configuration (voltage, filters) for the installed chips etc.

Comparing the two is not exactly the point of this article, but I can’t help myself doing that spec-wise, as both are advanced dual SID boards, with many similar features, and appearing around the same time.

The biggest difference between the two is actually the approach and design philosophy; SIDFX states being a plug and play, solder free solution that automatically detects the installed SID chips and configures itself accordingly. MixSID, in turn, is manually configured, comprehensively documented, open source, and DIY-friendly.

In fact, you can only have MixSID by building one yourself. You can go ahead and order or make your own pcbs, but Henning also sells the MixSID boards as kits, and I was sure to get myself one.

C64 Kickstarter Cases – With pictures!

The Kickstarter campaign for new C64 C cases using the original molds happened, and a lot of people have been very excited about that. Despite some ridiculous occurrences by Kickstarter (can’t show renders of the cases) and dimwits owning some rights to Commodore brand (can’t even mention Commodore in the campaign), the campaign was a real funding success.

Also the production phase faced an unfortunate incident, as the plastic molding company that produced the cases suffered a fire in the factory. The fire destroyed the transparent cases which had been the first ones pressed. Despite these shortcomings and delays the cases got pressed and sent out in the last couple of weeks. Related forums and social media groups have been filled with photos of these new cases and nice C64 setups installed in them.

I got mine last week, and guess what I’m going to do? Post some pictures of course! 

How about newly produced C64s?

Long time no posting. Once again there’s some interesting things going on in the C64 community. Especially one of the on-going funding campaigns I would like to bring to your attention.

First a quick recap.

C64 Reloaded. Image (c) Individual Computers

Already last year on April Fool’s Day Individual Computers announced the C64 Reloaded. Being no joke, it’s a newly produced C64 motherboard using the original chipset to celebrate C64’s 32th anniversary. After some changes in pricing and availability schedule, these new motherboards should be available on Individual Computers’ web shop shortly.

New C64 C cases. Render (c) Thomas Koch

More recently, on March 2015 an interesting Kickstarter project surfaced. It was for newly produced C64 C casings using the original molds. The project has an interesting back story, and the project funding goal of $ 10,000 was met in no less than a day! Eventually, the Kicstarter for the new colored and transparent C64 cases was so popular, that the initial funding goal was filled almost ten-fold. The cases are in production at the moment, and backers should receive their rewards sometime soon.

As to complete the lineup, there is now another crowd funding project going on for new C64 key caps in various colors. The funding goal is quite high, € 25,000. This is no wonder, as this time also the molds for the casting process has to be made. At the time of writing, roughly 60 % of the funding has been met, and the funding period will last for one and half weeks still, ending somewhere around 28th May 2015.

The C64 Reloaded and new C64 casings already came true. I’m hoping that also this third re-manufacturing project becomes reality. Not only hoping, I’m of course backing also on this effort, and I would like to encourage you to do so too!

SwinSID analog controller hack

I’ve covered SwinSID micro and nano few times before. It’s a great idea – a micro controller based SID chip replacement, working as a spare part  for a C64 or C128, or as a substitute to some other application like a DIY-synth. For Commodores, it’s especially suited for a gaming machine, as only very few games feature such tricks that would not sound about right on the SwinSID.

However, there’s this downside with the SwinSID that it does not support analog controllers. This is because it’s the SID chip that handles the reading of analog controllers in the C64, and the A/D converters are not implemented in the SwinSID. The number of games supporting paddles, mice or analog joysticks is not that big, but still it’s a shame that they won’t work with SwinSID. Also the few games that support second joystick button are affected. They behave as if the second button would be triggered constantly.

So there is a lack of fully featured replacement for a SID chip. This is a shame as SID chips are sought after, and supply for good and working chips is getting more and more scarce. The demand of SID chips have been recognized, as it’s not that difficult to find a supply of SID chips from Asia. It’s just that many have found out that these chips are often dead, faulty or downright fakes, and often rebadged.

Knowing that there are a lot of these faulty SID chips with bad filters or missing sound channels, it had occurred to me that maybe these could be combined together with SwinSID to make at least a fully featured replacement for the SID chip. Sound from the SwinSID, and A/D converters from an otherwise faulty SID.

Recently I ordered some spare parts from Mutant Caterpillar Games, who have a selection of chips for 8-bit computers in stock, including SID chips. As we were talking together with Ian Gledhill about SID sourcing challenges among other things I mentioned this idea of mine. He kindly sent me few faulty rebadged SID chips to test it out.

So, off I am to build an adapter that allows me to install SwinSID and a ‘badSID’ to the C64.

C64 A/V cable – theory and practice

A while ago I made a proper SCART cable for Amiga, so why not for C64 as well? So what I did was a C64 SCART cable with selectable composite/S-Video mode, including a ‘chroma fix’ and audio noise reduction ‘mod’ plus a preparation for possible stereo audio use. But let’s start with the theory.

Cable making principle

Building an A/V cable for C64 is not very difficult. In the simplest form, what is needed are plug for the C64 Video port, a cable with enough wires for the desired operation and the output connector(s).

C64 Video port

The C64 Video port is an 8-pin DIN connector, which is a standard multi purpose connector. It means that the required DIN plugs are easy to find and cheap. However, there are two different versions of the 8-pin DIN plug. The two versions differ in the shape of the arc that the pins form. Best shown as a picture:

The two pins marked in grey in the wrong type DIN plug will prevent the plug from being inserted into C64 A/V jack. But not to worry in case you’re holding the wrong type of plug in your hand, these two pins can be cut off or pulled out from the connector plug. In any ordinary A/V cable they are not needed anyway. Here is the Video port pinout:

Some early C64s had a 5-pin Video port that are missing the pins 6-8. It means there’s not separate chroma signal available there. In other words: no S-Video, only composite available via the video port.

Make note on the pin 8. It is either directly wired to the +5V DC line from the PSU (after the power switch) or not connected. According to my first hand research, the +5V DC line is present in the C64 Video port in all but the earliest two models. The +5V line is present starting from model C64B, or motherboard ASSY-NO. 250425. That means machines manufactured starting from 1984.

Stereo to C64 with DualSID

I finally assembled one of my DualSID kits. It’s an add-on board for C64 that makes it possible to install an additional SID chip with several different configurations. Detailed description can be found at the DualSID home page or in my earlier post.

Update in April 2018: The DualSID home page is gone, so I add the latest(?) versions of the assembly instructions here, plus link to Lemon64 forums.

• dualsid_assembling_instructions_6581_v3
• dualsid_assembling_instructions_8580_v3
• Discussion, mods and fixes on Lemon64 thread

Note: the transistor orientation is incorrect in the pcb silk screen in pcbs prior to pcb v3. However, letters E, B, C are printed correctly on the board, so check your transistor pinout. Pictures seen on this post have the transistor installed wrong way around. Transistor’s flat edge should face towards edge of the board. I’ve fixed mine since. </update>

I made this one as the 8580 version. Here’s the board – without and with SID chips.

For the convinience of installing it from one C64 to another if needed, I made all external connections and jumper settings using pin headers. When the board is like this, the second SID address selection is done by setting the jumper block in the 2×4 pin header to correct position. Instead of manually changing the jumper block’s position, I’m able to replace the block with 2×4 female pin header that is wired to e.g. a rotary swithch. That way the changing of second SID address can be done externally.